Chapter 1: Jiu Zhen Shi Er Yuan (nine kinds of needles, twelve Yuan points）九针十二原第一
1. Inserting a needle, and catching "ji"
Article I "Xiao zhen zhi yao. Yi cheng er nan ru. Cu shou xing, Shang shou shen" 小针之要，易陈而难入，粗守形，上守神，
= "The small needle principle is easy to describe but difficult to do. A doctor who is not careful pays attention to the body, a superior (good) doctor pays attention to the Shen".
Article II "Ci zhi wei, zai su chi, Cu Chu shou guan, shang shou ji" 刺之微，在速迟，粗守关，上守机，
= "The feeling at the insertion of the needle depends on fast or slow insertion. A doctor who is not careful pays attention to the location of the point, a good doctor catches ji"
"Ji zhi dong, bu li qi kong; kong zhong zhi ji, qing jing er wei; qi lai bu ke feng, qi wang bu ke zui" 机之动，不离其空，空中之机，清静而微，其来不可逢，其往不可追
= "The changing of ji gives an atmosphere; Qi, in this atmosphere, is quiet, clear and weak like a mirror; waiting (to insert the needle) it might not come, where it goes (when it is gone) you cannot catch" Note: It means that what is important is to catch "it" or the opportunity in the atmosphere and just at the right time insert the needle.
From Dr. Li Xin, Dr.Claudine Merer TCM : BACK TO THE SOURCES FOR A MODERN APPROACH P314